My invention relates to a coupling arrangement for power line carrier systems, and particularly to such a coupling arrangement that provides redundancy and greater reliability.
Carrier systems designed to operate over power transmission lines should be extremely reliable. Where such carrier systems provide switching or relaying functions, the highest degree of reliability is required because of the large number of customers served by such power lines. Consequently, such power lines should be kept in service if no fault exists. However, because of the great value and cost of power equipment and lines, the power lines should be removed from service if a fault does occur.
Accordingly, a primary object of my invention is to provide a new and more reliable arrangement for coupling carrier systems to a power line.
Another object of my invention is to provide a new and improved arrangement that uses redundant paths to couple different carrier systems to power lines, and that provides good isolation between the carrier systems.
Another object of my invention is to provide a new and improved redundant arrangement for coupling carrier systems to power lines with relatively small coupling loss.
A relatively specific object of my invention is to provide a new arrangement for coupling each of two carrier systems to each of three phase wires of a power transmission line to provide reliable operation of the carrier systems.
Redundant arrangements for coupling carrier systems to power lines have been provided before. For example, an arrangement for coupling two carrier systems to each of two phase wires is taught in a conference paper by H. J. Sutton entitled "Power Line Carrier Tests on a 500 KV Line", and presented at a Texas A&M Relay Conference on Apr. 16, 1973. However, that arrangement couples the carrier systems to only two phase wires of a power transmission line, and hence was subject to relatively large transmission line losses. Also four relatively costly coupling capacitors are required instead of three.
Accordingly, another object of my invention is to provide a new and improved arrangement for coupling two carrier systems to each of three phase wires of a power transmission line so as to obtain relatively efficient transmission and low loss over the phase wires.